How to Clean an Old Oil Painting Done on Canvas
- 1). Cut a piece of cardboard to fit inside the back of the stretcher. Put books or blocks under the cardboard to reach the height of the stretchers. Rest the painting on the horizontal surface to support it while you are working.
- 2). Look at the painting's surface with a magnifying glass. Small dots, often caused by insect excrement, can be scraped off very carefully with a scalpel. Attempt to remove surface dirt, soot and dust by cleaning with a solution of water and gentle soap if the painting has no cracks or peeling paint. After testing a corner of the canvas, carefully clean small areas of the painting at a time. Wet the canvas as little as possible.
- 3). Remove the coat of varnish from a painting if it is discolored. Mix an initial solution of one part alcohol and one part turpentine. Test this solution out on a small corner area by applying a little bit of solvent on a cotton swab. If the solution removes any pigment, decrease the proportion of alcohol or discontinue the removal of the varnish. If the solution is not strong enough to remove the varnish, increase the amount of alcohol. Work in small sections until you have removed all of the varnish, checking the swabs frequently for signs of paint.